Mary DiNunzio faces two daunting changes in bestseller Scottoline’s intriguing 12th novel featuring the all-woman Philadelphia law firm of Rosato & Associates (after 2010’s Think Twice): she has become a partner in the firm, which affects her relationships with former fellow associates; and boyfriend Anthony Rotunno gets a lot more serious. Mary’s first client as a partner is 13-year-old Allegra Gardner, who wants to retain the firm to prove that Lonnie Stall, imprisoned for the murder of Allegra’s older sister, Fiona, six years earlier, is innocent and to find the real killer. Allegra may be precocious, and she has her own funds, but her wealthy parents oppose her actions directly and forcibly. Myriad legal and ethical problems complicate the case, including Stall’s own confession, as does the help, wanted and unwanted, of the DiNunzio and Rotunno families. Mary follows her heart and gut into danger in this welcome series return after three stand-alones. First printing of 400,000. Agent: Molly Friedrich, Friedrich Literary Agency. (Oct.)